Many medicament products are provided for sale in a blister-type package in which an individual medicament, typically in the form of a caplet, tablet, or capsule, is sealed into an individual compartment from which it can be removed without disturbing the other medicaments. Blister packages typically include a base sheet of plastic material that is molded or thermoformed to provide a tray having a plurality of recesses or cavities that are each adapted to hold an individual medicament. A lidding, also referred to as a backing or retaining sheet, is attached to the base sheet so that it overlies the plurality of cavities and encloses each of the medicaments in their respective cavities.
Many blister packages are designed so the areas of the lidding can be ruptured or opened to provide access to an individual cavity. For example, in one common form of blister package, the lidding comprises a thin sheet of metal foil, such as aluminum, that can be ruptured by pushing on the cavity so that the caplet or tablet ruptures the foil sheet. This form of blister package is commonly referred to as a “push through” type blister package. While this form of blister package generally allows easy access to the medicament, it can pose a safety concern to children because of ease of access. In particular, this form of lidding typically has poor bite resistance. One approach of addressing this problem has been to increase the thickness of the foil sheet to make it more difficult for a child to rupture the foil sheet. However, this can make it more difficult for the elderly and infirm to gain access to their medicament.
Another approach is the so-called “peel push” type blister package. In this approach, the lidding is a multilayer structure in which a polymeric film or paper layer is adhesively attached to a rupturable metal foil layer. The thermoplastic film layer provides bite resistance to the package. The adhesive interface between the metal foil layer and the thermoplastic film layer is weakened so that the film layer can be peeled back so as to expose the rupturable foil layer. Once the film layer has been removed, the medicament can be removed from the package by pushing the medicament through the foil layer as described above. This form of blister package has become the standard blister package for providing child and bite resistant packages.
However, the peel push form of blister package has several disadvantages. In particular, it can be difficult to open, particularly for the elderly or the infirm. Additionally, there have been some issues with the consistency of the peel strength between the thermoplastic film layer and the rupturable foil layer, which may lead to difficulties in access for some patients.
Accordingly, there still exists a need for an improved blister package that is child and bite resistant and that can still be easily opened by the elderly and infirmed.